1. Field of the Invention
The invention concerns a method for mounting a rotor blade of a wind power installation without using a crane and a wind power installation implementing said method.
2. Description of the Related Art
It has already long been known to use mobile cranes for mounting rotor blades to a wind power installation. Such cranes pick up the rotor blade at the base of the wind power installation and take it to the rotor blade connection of the hub of the wind power installation so that the rotor blade can be connected to the hub. That connection is usually made by screw means, in which case screw bolts are let into the connecting flange of the rotor blade and project into corresponding bores in the rotor blade connection of the hub so that nuts can be screwed on to the screw bolts and in that way the rotor blade is fixed to the hub.
As published state of the art attention is directed in particular to the book by Hau, Erich: Windkraftanlagen, 1996. It is also known, in place of a mobile crane, to use a stationary crane which is mounted on the machine housing of the wind power installation. That stationary crane is provided with a cable winch and a winch drive so that the rotor blade at the base of the wind power installation is drawn upwardly to the rotor blade connection and can then be connected thereto.
A disadvantage of mobile cranes is that they must always be on site when the rotor blades are to be mounted to the hub of the wind power installation with such cranes. As almost all other parts of the machine housing are also fitted with those mobile cranes, the rotor blade must be on the building site at the same time with those parts, in order to be able to make best possible use of the mobile cranes, so that all essential parts of the machine housing of the wind power installation, together with all rotor parts, can be mounted with a single use of the crane. If however it is not possible for the rotor blades to be delivered to the building site at the correct time, then either the crane has to wait for the arrival of the rotor blade or as an alternative thereto the crane has to be brought to the site again so that the blade mounting operation can be effected when the rotor blades are delivered.
A disadvantage of stationary cranes is that usually they can also only be mounted on the machine housing of the wind power installation by means of a mobile crane and in addition, if such stationary cranes remain on the machine housing, they are only extremely rarely used so that the costs involved with such stationary crane installations are scarcely reasonably related to the benefit thereof.